Add a BSD licensed QR code library

resources/qr_code/QRMath.php

@@ -0,0 +1,145 @@
+<?php
+/**
+ * This file is part of the phpQr package
+ *
+ * See @see QRCode class for description of package and license.
+ */
+
+/**
+ * Import necessary dependencies
+ */
+require_once 'QRCodeException.php';
+
+/**
+ * Derived exception
+ * 
+ * @author Maik Greubel <greubel@nkey.de>
+ * @package phpQr
+ */
+class QRMathException extends QRCodeException
+{
+}
+
+/**
+ * QR Code math helper class
+ *
+ * @author Maik Greubel <greubel@nkey.de>
+ * @package phpQr
+ */
+final class QRMath
+{
+  /**
+   * Exponent table
+   *
+   * @var array
+   */
+  private $EXP_TABLE = null;
+  
+  /**
+   * Logarithm table
+   * 
+   * @var array
+   */
+  private $LOG_TABLE = null;
+  
+  /**
+   * Singleton pattern
+   * 
+   * @var QRMath
+   */
+  private static $instance = null;
+  
+  /**
+   * Singleton pattern
+   *
+   * @return QRMath Singleton
+   */
+  public static function getInstance()
+  {
+    if (! self::$instance)
+    {
+      self::$instance = new self ();
+    }
+    
+    return self::$instance;
+  }
+  
+  /**
+   * Create a new instance of QRMath
+   */
+  private function __construct()
+  {
+    $this->init ();
+  }
+  
+  /**
+   * Initialize the tables
+   */
+  private function init()
+  {
+    $this->EXP_TABLE = array ();
+    for($i = 0; $i < 8; $i ++)
+    {
+      $this->EXP_TABLE [$i] = 1 << $i;
+    }
+    
+    for($i = 8; $i < 256; $i ++)
+    {
+      $this->EXP_TABLE [$i] = $this->EXP_TABLE [$i - 4] ^ $this->EXP_TABLE [$i - 5] ^ $this->EXP_TABLE [$i - 6] ^ $this->EXP_TABLE [$i - 8];
+    }
+    
+    $this->LOG_TABLE = array ();
+    for($i = 0; $i < 255; $i ++)
+    {
+      $this->LOG_TABLE [$this->EXP_TABLE [$i]] = $i;
+    }
+  }
+  
+  /**
+   * Get logarithm of n
+   *
+   * @param int $n          
+   * @throws QRMathException
+   * @return int
+   */
+  public function glog($n)
+  {
+    if ($n < 1)
+    {
+      throw new QRMathException ( "glog(" . $n . ")" );
+    }
+    
+    foreach ( $this->LOG_TABLE as $key => $value )
+    {
+      if ($key == $n)
+        return $value;
+    }
+    
+    throw new QRMathException ( "glog($n)" );
+  }
+  
+  /**
+   * Get the exponent of n
+   *
+   * @param int $n          
+   * @return int
+   */
+  public function gexp($n)
+  {
+    while ( $n < 0 )
+    {
+      $n += 255;
+    }
+    while ( $n >= 256 )
+    {
+      $n -= 255;
+    }
+    foreach ( $this->EXP_TABLE as $key => $value )
+    {
+      if ($key == $n)
+        return $value;
+    }
+    
+    throw new QRMathException ( "gexp($n)" );
+  }
+}